Has Regulatory Action Reduced Human Exposure to Flame Retardants?

Flame retardant (FR) exposure has been linked to several environmental and human health effects. Because of this, the production and use of several FRs are regulated globally. We reviewed the available records of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) in human breast milk from literature to evaluate the efficacy of regulation to reduce the exposure of FRs to humans. Two-hundred and seven studies were used for analyses to determine the spatial and temporal trends of FR exposure. North America consistently had the highest concentrations of PBDEs, while Asia and Oceania dominated HBCDD exposure. BDE-49 and -99 indicated decreasing temporal trends in most regions. BDE-153, with a longer half-life than the aforementioned isomers, typically exhibited a plateau in breast milk levels. No conclusive trend could be established for HBCDD, and insufficient information was available to determine a temporal trend for BDE-209. Breakpoint analyses indicated a significant decrease in BDE-47 and -99 in Europe around the time that regulation has been implemented, suggesting a positive effect of regulation on FR exposure. However, very few studies have been conducted globally (specifically in North America) after 2013, during the time when the most recent regulations have been implemented. This meta-analysis provides insight into global trends in human exposure to PBDEs and HBCDD, but the remaining uncertainty highlights the need for ongoing evaluation and monitoring, even after a compound group is regulated.

Table S1 Comparisons

Figure S1 .
Figure S1.Overview of data selection steps for literature review to identify reports of HBCDDs and PBDEs in human milk

Figure S4 .
Figure S4.Weighted temporal trends of a) BDE-99, and b) BDE-209 concentrations (ng/g lipid weight, lw) in breast milk from North America from literature.Shaded area indicates 95 th confidence internval

Figure S7 .
Figure S7.Weighted temporal trends of a) BDE-47, b) BDE-99, c) BDE-153, d) α-HBCDD concentrations (ng/g lipid weight, lw) in breast milk from Central and South America and the Caribbean from literature.Shaded area indicates 95th percent confidence interval .

Figure S9 .
Figure S9.Results of breakpoint analysis for BDE-47 in human milk in (a) Central and South America and the Caribbean, (b) North America, and (c) Oceania.Shaded area indicates 95 th percent confidence interval.

Figure S10 .
Figure S10.Results of breakpoint analysis for BDE-99 in human milk for (a) Central and South America and the Caribbean, (b) North America, and (c) Oceania.Shaded area indicates 95th percent confidence interval.

Figure S11 .
Figure S11.Results of breakpoint analysis for BDE-153 in human milk for (a) North America and (b) Oceania.Shaded area indicates 95th percent confidence interval.

Figure
Figure S12 Results of breakpoint analysis for BDE-209 in human milk for North America.Shaded area indicates 95th percent confidence interval. ).

Table S2
Previous studies evaluating time trends in PBDE concentrations in human biomonitoring matrices.

Table S3
Previous studies evaluating time trends in HBCDD concentrations in human biomonitoring matrices.